From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Kim Phillips <kim.phillips@freescale.com>
Cc: "Woodhouse, David" <david.woodhouse@intel.com>,
Borislav Petkov <bp@alien8.de>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Santos <daniel.santos@pobox.com>,
David Rientjes <rientjes@google.com>,
Rusty Russell <rusty@rustcorp.com.au>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Rob Herring <robherring2@gmail.com>
Subject: Re: [RFC] arm: use built-in byte swap function
Date: Thu, 31 Jan 2013 09:28:01 +0000 [thread overview]
Message-ID: <20130131092801.GV23505@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20130130200900.9d7cf7908caeaef4ecee1d61@freescale.com>
On Wed, Jan 30, 2013 at 08:09:00PM -0600, Kim Phillips wrote:
> The savings come mostly from device-tree related code, and some
> from drivers.
You forget that IP networking is all big endian, so these will be using
the byte swapping too (search it for htons/ntohs/htonl/ntohl).
> v2:
> - at91 and lpd270 builds fixed by limiting to ARMv6 and above
> (i.e., ARM cores that have support for the 'rev' instruction).
> Otherwise, the compiler emits calls to libgcc's __bswapsi2 on
> these ARMv4/v5 builds (and arch ARM doesn't link with libgcc).
Which compiler version? gcc 4.5.4 doesn't do this, except for the 16-bit
swap, so I doubt that any later compiler does.
> --- a/arch/arm/include/uapi/asm/swab.h
> +++ b/arch/arm/include/uapi/asm/swab.h
> @@ -50,4 +50,14 @@ static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
>
> #endif
>
> +#if defined(__KERNEL__) && __LINUX_ARM_ARCH__ >= 6
> +#if GCC_VERSION >= 40600
> +#define __HAVE_BUILTIN_BSWAP32__
> +#define __HAVE_BUILTIN_BSWAP64__
> +#endif
> +#if GCC_VERSION >= 40800
> +#define __HAVE_BUILTIN_BSWAP16__
> +#endif
> +#endif
If this is __KERNEL__ only, it should not be in a uapi header. UAPI
headers get exported to userland, this is not userland interface code.
IT should be in arch/arm/include/asm/swab.h
WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] arm: use built-in byte swap function
Date: Thu, 31 Jan 2013 09:28:01 +0000 [thread overview]
Message-ID: <20130131092801.GV23505@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20130130200900.9d7cf7908caeaef4ecee1d61@freescale.com>
On Wed, Jan 30, 2013 at 08:09:00PM -0600, Kim Phillips wrote:
> The savings come mostly from device-tree related code, and some
> from drivers.
You forget that IP networking is all big endian, so these will be using
the byte swapping too (search it for htons/ntohs/htonl/ntohl).
> v2:
> - at91 and lpd270 builds fixed by limiting to ARMv6 and above
> (i.e., ARM cores that have support for the 'rev' instruction).
> Otherwise, the compiler emits calls to libgcc's __bswapsi2 on
> these ARMv4/v5 builds (and arch ARM doesn't link with libgcc).
Which compiler version? gcc 4.5.4 doesn't do this, except for the 16-bit
swap, so I doubt that any later compiler does.
> --- a/arch/arm/include/uapi/asm/swab.h
> +++ b/arch/arm/include/uapi/asm/swab.h
> @@ -50,4 +50,14 @@ static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
>
> #endif
>
> +#if defined(__KERNEL__) && __LINUX_ARM_ARCH__ >= 6
> +#if GCC_VERSION >= 40600
> +#define __HAVE_BUILTIN_BSWAP32__
> +#define __HAVE_BUILTIN_BSWAP64__
> +#endif
> +#if GCC_VERSION >= 40800
> +#define __HAVE_BUILTIN_BSWAP16__
> +#endif
> +#endif
If this is __KERNEL__ only, it should not be in a uapi header. UAPI
headers get exported to userland, this is not userland interface code.
IT should be in arch/arm/include/asm/swab.h
next prev parent reply other threads:[~2013-01-31 9:28 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-29 1:30 [RFC] arm: use built-in byte swap function Kim Phillips
2013-01-29 1:30 ` Kim Phillips
2013-01-29 8:35 ` Borislav Petkov
2013-01-29 8:35 ` Borislav Petkov
2013-01-29 16:46 ` Woodhouse, David
2013-01-29 16:46 ` Woodhouse, David
2013-01-29 17:42 ` Borislav Petkov
2013-01-29 17:42 ` Borislav Petkov
2013-01-29 17:55 ` Woodhouse, David
2013-01-29 17:55 ` Woodhouse, David
2013-01-29 18:10 ` Borislav Petkov
2013-01-29 18:10 ` Borislav Petkov
2013-01-30 10:22 ` Woodhouse, David
2013-01-30 10:22 ` Woodhouse, David
2013-01-31 2:09 ` Kim Phillips
2013-01-31 2:09 ` Kim Phillips
2013-01-31 6:44 ` Borislav Petkov
2013-01-31 6:44 ` Borislav Petkov
2013-01-31 9:28 ` Russell King - ARM Linux [this message]
2013-01-31 9:28 ` Russell King - ARM Linux
2013-01-31 20:59 ` Kim Phillips
2013-01-31 20:59 ` Kim Phillips
2013-01-31 21:33 ` Borislav Petkov
2013-01-31 21:33 ` Borislav Petkov
2013-01-31 22:11 ` Woodhouse, David
2013-01-31 22:11 ` Woodhouse, David
2013-02-01 0:37 ` [PATCH v4] " Kim Phillips
2013-02-01 0:37 ` Kim Phillips
2013-02-01 10:46 ` Russell King - ARM Linux
2013-02-01 10:46 ` Russell King - ARM Linux
2013-02-01 1:17 ` [RFC] " Russell King - ARM Linux
2013-02-01 1:17 ` Russell King - ARM Linux
2013-02-01 7:33 ` Woodhouse, David
2013-02-01 7:33 ` Woodhouse, David
2013-02-06 3:04 ` Kim Phillips
2013-02-06 3:04 ` Kim Phillips
2013-02-06 9:02 ` Woodhouse, David
2013-02-06 9:02 ` Woodhouse, David
2013-02-07 1:19 ` Kim Phillips
2013-02-07 1:19 ` Kim Phillips
2013-02-07 10:19 ` Will Newton
2013-02-07 10:19 ` Will Newton
2013-02-07 10:43 ` Catalin Marinas
2013-02-07 10:43 ` Catalin Marinas
2013-02-07 18:13 ` Russell King - ARM Linux
2013-02-07 18:13 ` Russell King - ARM Linux
2013-02-08 17:25 ` Woodhouse, David
2013-02-08 17:25 ` Woodhouse, David
2013-02-08 20:04 ` Nicolas Pitre
2013-02-08 20:04 ` Nicolas Pitre
2013-02-08 22:40 ` Woodhouse, David
2013-02-08 22:40 ` Woodhouse, David
2013-02-08 22:47 ` Nicolas Pitre
2013-02-08 22:47 ` Nicolas Pitre
2013-02-09 1:12 ` Kim Phillips
2013-02-09 1:12 ` Kim Phillips
2013-02-09 3:16 ` Nicolas Pitre
2013-02-09 3:16 ` Nicolas Pitre
2013-02-20 2:31 ` Kim Phillips
2013-02-20 2:31 ` Kim Phillips
2013-02-20 2:38 ` Stephen Boyd
2013-02-20 2:38 ` Stephen Boyd
2013-02-20 3:17 ` Nicolas Pitre
2013-02-20 3:17 ` Nicolas Pitre
2013-02-20 10:38 ` Woodhouse, David
2013-02-20 10:38 ` Woodhouse, David
2013-02-20 13:36 ` Nicolas Pitre
2013-02-20 13:36 ` Nicolas Pitre
2013-02-20 13:44 ` Woodhouse, David
2013-02-20 13:44 ` Woodhouse, David
2013-02-20 14:06 ` Nicolas Pitre
2013-02-20 14:06 ` Nicolas Pitre
2013-02-20 14:53 ` Woodhouse, David
2013-02-20 14:53 ` Woodhouse, David
2013-02-20 15:43 ` Nicolas Pitre
2013-02-20 15:43 ` Nicolas Pitre
2013-02-21 3:49 ` Kim Phillips
2013-02-21 3:49 ` Kim Phillips
2013-02-21 4:29 ` Nicolas Pitre
2013-02-21 4:29 ` Nicolas Pitre
2013-02-21 6:52 ` Kim Phillips
2013-02-21 6:52 ` Kim Phillips
2013-02-21 16:40 ` Nicolas Pitre
2013-02-21 16:40 ` Nicolas Pitre
2013-02-22 2:33 ` Kim Phillips
2013-02-22 2:33 ` Kim Phillips
2013-02-22 3:40 ` Nicolas Pitre
2013-02-22 3:40 ` Nicolas Pitre
2013-02-23 1:40 ` [PATCH v6] " Kim Phillips
2013-02-23 1:40 ` Kim Phillips
2013-02-23 2:40 ` Nicolas Pitre
2013-02-23 2:40 ` Nicolas Pitre
2013-02-23 23:20 ` Woodhouse, David
2013-02-23 23:20 ` Woodhouse, David
2013-05-23 16:46 ` [PATCH v7] " Kim Phillips
2013-05-23 16:46 ` Kim Phillips
2013-05-23 20:09 ` Nicolas Pitre
2013-05-23 20:09 ` Nicolas Pitre
2013-05-23 23:13 ` Russell King - ARM Linux
2013-05-23 23:13 ` Russell King - ARM Linux
2013-06-06 22:12 ` Russell King - ARM Linux
2013-06-06 22:12 ` Russell King - ARM Linux
2013-06-06 22:23 ` Borislav Petkov
2013-06-06 22:23 ` Borislav Petkov
2013-06-07 0:03 ` Stephen Rothwell
2013-06-07 0:03 ` Stephen Rothwell
2013-05-26 5:38 ` Dirk Behme
2013-05-26 9:30 ` Woodhouse, David
2013-10-27 2:41 ` Nicolas Pitre
2013-10-27 2:41 ` Nicolas Pitre
2013-11-05 21:45 ` Kim Phillips
2013-11-05 21:45 ` Kim Phillips
2013-02-21 16:37 ` [RFC] " Woodhouse, David
2013-02-21 16:37 ` Woodhouse, David
2013-02-21 17:27 ` Nicolas Pitre
2013-02-21 17:27 ` Nicolas Pitre
2013-03-13 13:35 ` Woodhouse, David
2013-03-13 13:35 ` Woodhouse, David
2013-01-29 14:13 ` Russell King - ARM Linux
2013-01-29 14:13 ` Russell King - ARM Linux
2013-01-29 14:43 ` Woodhouse, David
2013-01-29 14:43 ` Woodhouse, David
2013-01-29 14:53 ` Rob Herring
2013-01-29 14:53 ` Rob Herring
2013-01-29 15:10 ` Woodhouse, David
2013-01-29 15:10 ` Woodhouse, David
2013-01-31 11:44 Woodhouse, David
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